The present invention relates generally to medical devices, and more particularly relates to tracheal stent devices.
There are many indications for tracheostomy, in which a device known as a tracheostomy tube is typically inserted into the trachea for inhalation purposes. The tracheostomy tube is basically a curved plastic tube fitted adjacent its distal end (which is inserted downwardly into the trachea through a suitable next incision) therein with an external balloon or cuff element which may be selectively inflated within the trachea to retain the tube in place and allow for mechanical ventilation. With the tracheostomy tube in place, the outer tube end is operatively connected to a ventilator which functions to cyclically force air downwardly through the inserted tube into the tracheal passage portion below it, and into the patient's lungs.
Conventional balloon-tipped tracheostomy tubes often cause interior tracheal scarring which restricts the tracheal passage. This scarring typically arises due to the fact that the curved tracheostomy tube does not conform to the essentially straight tracheal anatomy, and leads to pressure necrosis of the wall of the trachea, and from the pressure forces imposed on the interior surface of the trachea by the inflated retention balloon.
Upon removal of the tracheostomy tube, this interior scarring, which tends to restrict the trachea, may necessitate the subsequent insertion into the trachea of a device known as a T-tube stent, or a "Montgomery tube", which functions to hold the scarred and restricted tracheal portion open and prevent it from unduly restricting patient breathing. The typical T-tube stent utilized in this manner is illustrated in U.S. Pat. No. 3,721,233 to Montgomery et al. and includes a hollow, open-ended tubular body portion which is coaxially inserted into the trachea, and a hollow transverse central leg portion which passes outwardly through the tracheal insertion incision and is suitably stoppered at its outer end.
While the subsequent use of conventional T-tube stents in this manner is quite beneficial in holding open scar tissue-restricted tracheal passage areas during patient recuperation, it does not permit the use of a ventilator to assist the patient's breathing. Air forced into the outwardly projecting transverse stent portion cannot be effectively forced downwardly into the patient's lungs because both the upper and lower ends of the inserted T-tube body within the trachea are open, and air passes preferentially out the mouth because of less resistance.
From the foregoing it can be readily seen that the conventional sequential use of curved tracheostomy tubes and T-tube stents in the tracheal area is, for a variety of reasons, not wholly satisfactory. It is accordingly an object of the present invention to provide improved apparatus less traumatic to the trachea which can also hold the trachea open and permit the use of an inhalator to assist a patient's breathing when necessary. This then may prevent scarring produced by conventional hard plastic tracheostomy appliances as well as allow a greater application to patients with early scarring who still require ventilatory assistance.